5-128332950-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2 PP2 PP3_Strong PP5_Moderate

The NM_001999.4(FBN2):c.4184G>A(p.Cys1395Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C1395F) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: FBN2 NM_001999.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.91

Genes affected

FBN2 (HGNC:3604): (fibrillin 2) The protein encoded by this gene is a component of connective tissue microfibrils and may be involved in elastic fiber assembly. Mutations in this gene cause congenital contractural arachnodactyly. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, FBN2
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.996
• PP5: Variant 5-128332950-C-T is Pathogenic according to our data. Variant chr5-128332950-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1509864.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FBN2	NM_001999.4	c.4184G>A	p.Cys1395Tyr	missense_variant	32/65	ENST00000262464.9
FBN2	XM_017009228.3	c.4031G>A	p.Cys1344Tyr	missense_variant	31/64

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FBN2	ENST00000262464.9	c.4184G>A	p.Cys1395Tyr	missense_variant	32/65	1	NM_001999.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital contractural arachnodactyly Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jan 16, 2022

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant affects a cysteine residue located within an epidermal growth factor (EGF)–like domain of the FBN2 protein. Cysteine residues in these domains are involved in the formation of disulfide bridges critical for protein structure and stability (PMID: 3495735, 4750422, 16677079). In addition, missense substitutions within the FBN2 EGF-like domains affecting cysteine residues are overrepresented in patients with congenital contractural arachnodactyly (PMID: 18767143). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt FBN2 protein function. This variant has not been reported in the literature in individuals affected with FBN2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces cysteine, which is neutral and slightly polar, with tyrosine, which is neutral and polar, at codon 1395 of the FBN2 protein (p.Cys1395Tyr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
Cadd	Pathogenic	29
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D;.;D;D;D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.88	D;.;.;D;D
M_CAP	Pathogenic	0.86	D
MetaRNN	Pathogenic	1.0	D;D;D;D;D
MetaSVM	Pathogenic	0.93	D
MutationAssessor	Pathogenic	5.5	H;.;H;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-10	D;.;D;D;D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;.;D;D;D
Polyphen		1.0	D;.;D;.;D
Vest4		0.99
MutPred		1.0		Gain of ubiquitination at K1392 (P = 0.1128);.;Gain of ubiquitination at K1392 (P = 0.1128);.;.;
MVP		0.98
MPC		1.1
ClinPred		1.0	D
GERP RS		4.9
Varity_R		0.99
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr5-127668642;